Building Resilient Sync Workers: Circuit Breakers and Self-Healing Patterns
Learn how we designed our sync workers to handle failures gracefully using circuit breaker patterns, exponential backoff, and self-healing mechanisms that keep your data flowing even when APIs go down.
Sync workers are the backbone of any data integration platform. At Automate Anything, we've built over 30 sync workers that process millions of records daily. But building reliable sync workers isn't just about writing code that moves data from A to B — it's about handling the inevitable failures that occur in distributed systems.
**The Circuit Breaker Pattern**
Our circuit breakers monitor error rates for each integration endpoint. When failures exceed a configurable threshold (typically 50% over a 5-minute window), the circuit "opens" and stops making requests to the failing endpoint. This prevents cascading failures and gives the upstream service time to recover.
**Self-Healing Mechanisms**
When a circuit breaker opens, our self-healing system kicks in. It periodically sends "probe" requests to check if the service has recovered. Once it detects successful responses, the circuit gradually closes, ramping up traffic slowly to avoid overwhelming the recovering service.
**Exponential Backoff with Jitter**
For transient failures, we use exponential backoff with jitter. This means each retry waits progressively longer, with a random component to prevent "thundering herd" problems when multiple workers retry simultaneously.
These patterns have helped us achieve 99.9% uptime across all our sync workers, even when individual integrations experience outages.